There is currently a large divide between kernel development and the
development of EFI boot loaders. The idea behind this patch is to give
the kernel developers full control over the EFI boot process. As
H. Peter Anvin put it,

"The 'kernel carries its own stub' approach been very successful in
dealing with BIOS, and would make a lot of sense to me for EFI as
well."

This patch introduces an EFI boot stub that allows an x86 bzImage to
be loaded and executed by EFI firmware. The bzImage appears to the
firmware as an EFI application. Luckily there are enough free bits
within the bzImage header so that it can masquerade as an EFI
application, thereby coercing the EFI firmware into loading it and
jumping to its entry point. The beauty of this masquerading approach
is that both BIOS and EFI boot loaders can still load and run the same
bzImage, thereby allowing a single kernel image to work in any boot
environment.

The EFI boot stub supports multiple initrds, but they must exist on
the same partition as the bzImage. Command-line arguments for the
kernel can be appended after the bzImage name when run from the EFI
shell, e.g.

Shell> bzImage console=ttyS0 root=/dev/sdb initrd=initrd.img

v7:
 - Fix checkpatch warnings.

v6:

 - Try to allocate initrd memory just below hdr->inird_addr_max.

v5:

 - load_options_size is UTF-16, which needs dividing by 2 to convert
   to the corresponding ASCII size.

v4:

 - Don't read more than image->load_options_size

v3:

 - Fix following warnings when compiling CONFIG_EFI_STUB=n

   arch/x86/boot/tools/build.c: In function ‘main’:
   arch/x86/boot/tools/build.c:138:24: warning: unused variable ‘pe_header’
   arch/x86/boot/tools/build.c:138:15: warning: unused variable ‘file_sz’

 - As reported by Matthew Garrett, some Apple machines have GOPs that
   don't have hardware attached. We need to weed these out by
   searching for ones that handle the PCIIO protocol.

 - Don't allocate memory if no initrds are on cmdline
 - Don't trust image->load_options_size

Maarten Lankhorst noted:
 - Don't strip first argument when booted from efibootmgr
 - Don't allocate too much memory for cmdline
 - Don't update cmdline_size, the kernel considers it read-only
 - Don't accept '\n' for initrd names

v2:

 - File alignment was too large, was 8192 should be 512. Reported by
   Maarten Lankhorst on LKML.
 - Added UGA support for graphics
 - Use VIDEO_TYPE_EFI instead of hard-coded number.
 - Move linelength assignment until after we've assigned depth
 - Dynamically fill out AddressOfEntryPoint in tools/build.c
 - Don't use magic number for GDT/TSS stuff. Requested by Andi Kleen
 - The bzImage may need to be relocated as it may have been loaded at
   a high address address by the firmware. This was required to get my
   macbook booting because the firmware loaded it at 0x7cxxxxxx, which
   triggers this error in decompress_kernel(),

	if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
		error("Destination address too large");

Cc: Mike Waychison <mikew@google.com>
Cc: Matthew Garrett <mjg@redhat.com>
Tested-by: NHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1321383097.2657.9.camel@mfleming-mobl1.ger.corp.intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Ensure build doesn't silently continue despite read failure,
addressing a warning due to the unchecked call.
Signed-off-by: NDaniel J Blueman <daniel.blueman@gmail.com>
LKML-Reference: <AANLkTimxxTMU3=4ry-_zbY6v1xiDi+hW9y1RegTr8vLK@mail.gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

This integrates the XZ decompression code to the x86 pre-boot code.

mkpiggy.c is updated to reserve about 32 KiB more buffer safety margin for
kernel decompression.  It is done unconditionally for all decompressors to
keep the code simpler.

The XZ decompressor needs around 30 KiB of heap, so the heap size is
increased to 32 KiB on both x86-32 and x86-64.

Documentation/x86/boot.txt is updated to list the XZ magic number.

With the x86 BCJ filter in XZ, XZ-compressed x86 kernel tends to be a few
percent smaller than the equivalent LZMA-compressed kernel.
Signed-off-by: NLasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A relocatable kernel can be anywhere in lowmem -- and in the case of a
kdump kernel, is likely to be fairly high.  Since the early page
tables map everything from address zero up we need to make sure we
allocate enough brk that we can map all of lowmem if we need to.
Reported-by: NStanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Tested-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <4D0AD3ED.8070607@kernel.org>

The code is 32bit already, and can be used in 32bit routines.
Signed-off-by: NKees Cook <kees.cook@canonical.com>
LKML-Reference: <1289414154-7829-2-git-send-email-kees.cook@canonical.com>
Acked-by: NPekka Enberg <penberg@kernel.org>
Acked-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

The kernel decompression code parses the ELF header and then copies
the segment to the corresponding destination.  Currently it uses slow
byte-copy code.  This patch makes it use the string copy operations
instead.

In the test the copy performance can be improved very significantly after using
the string copy operation mechanism.
        1. The copy time can be reduced from 150ms to 20ms on one Atom machine
	2. The copy time can be reduced about 80% on another machine
		The time is reduced from 7ms to 1.5ms when using 32-bit kernel.
		The time is reduced from 10ms to 2ms when using 64-bit kernel.
Signed-off-by: NZhao Yakui <yakui.zhao@intel.com>
LKML-Reference: <1286502453-7043-1-git-send-email-yakui.zhao@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

It is a subset of <ctype.h> functionality, so name it ctype.h.  Also,
reorganize header files so #include statements are clustered near the
top as they should be.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
LKML-Reference: <4C5752F2.8030206@kernel.org>

This enables the decompressor output to be seen on the serial console.
Most of the code is shared with the regular boot code.

We could add printf to the decompressor if needed, but currently there
is no sufficiently compelling user.

-v2: define BOOT_BOOT_H to avoid include boot.h
-v3: early_serial_base need to be static in misc.c ?
-v4: create seperate string.c printf.c cmdline.c early_serial_console.c
     after hpa's patch that allow global variables in compressed/misc stage
-v5: remove printf.c related
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

In order for global variables and functions to work in the
decompressor, we need to fix up the GOT in assembly code.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <4C57382E.8050501@zytor.com>

This reverts commit b3b77c8c, which was
also totally broken (see commit 0d2daf5c that reverted the crc32
version of it).  As reported by Stephen Rothwell, it causes problems on
big-endian machines:

> In file included from fs/jfs/jfs_types.h:33,
>                  from fs/jfs/jfs_incore.h:26,
>                  from fs/jfs/file.c:22:
> fs/jfs/endian24.h:36:101: warning: "__LITTLE_ENDIAN" is not defined

The kernel has never had that crazy "__BYTE_ORDER == __LITTLE_ENDIAN"
model.  It's not how we do things, and it isn't how we _should_ do
things.  So don't go there.
Requested-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Linux does not define __BYTE_ORDER in its endian header files which makes
some header files bend backwards to get at the current endian.  Lets
#define __BYTE_ORDER in big_endian.h/litte_endian.h to make it easier for
header files that are used in user space too.

In userspace the convention is that

  1. _both_ __LITTLE_ENDIAN and __BIG_ENDIAN are defined,
  2. you have to test for e.g. __BYTE_ORDER == __BIG_ENDIAN.
Signed-off-by: NJoakim Tjernlund <Joakim.Tjernlund@transmode.se>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDenys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

Inhibit output from the kernel decompressor if the video information
is invalid.  This was already the case for 32 bits, make 64 bits
match.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
LKML-Reference: <tip-*@git.kernel.org>

Iomem has no special significance on x86.  Use the standard mem*
functions instead of trying to call other versions.  Some fixups
are needed to match the function prototypes.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
LKML-Reference: <1265380629-3212-6-git-send-email-brgerst@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The necessary changes to the x86 Kconfig and boot/compressed to allow the
use of this new compression method
Signed-off-by: NAlbin Tonnerre <albin.tonnerre@free-electrons.com>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Tested-by: NWu Zhangjin <wuzhangjin@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: NRussell King <rmk@arm.linux.org.uk>
Acked-by: NRussell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Recently, some distros have started shipping versions of gcc which
default to -march=i686.  This breaks building kernels for pre-i686
machines, even if they have been selected in Kconfig, due to the
generation of CMOV instructions.

There isn't enough benefit to try to preserve the generation of these
instructions even when selected, so simply force -march=i386 for the
decompressor when building a 32-bit kernel.
Reported-and-tested-by: NChris Rankin <rankincj@yahoo.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
LKML-Reference: <219280.97558.qm@web52907.mail.re2.yahoo.com>

This adds a new category of symbols to the relocs program: symbols
which are known to be relative, even though the linker emits them as
absolute; this is the case for symbols that live in the linker script,
which currently applies to _end.

Unfortunately the previous workaround of putting _end in its own empty
section was defeated by newer binutils, which remove empty sections
completely.

This patch also changes the symbol matching to use regular expressions
instead of hardcoded C for specific patterns.

This is a decidedly non-minimal patch: a modified version of the
relocs program is used as part of the Syslinux build, and this 	is
basically a backport to Linux of some of those changes; they have
thus been well tested.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
LKML-Reference: <4AF86211.3070103@zytor.com>
Acked-by: NMichal Marek <mmarek@suse.cz>
Tested-by: NSedat Dilek <sedat.dilek@gmail.com>

Rather than having X86_L1_CACHE_BYTES and X86_L1_CACHE_SHIFT
(with inconsistent defaults), just having the latter suffices as
the former can be easily calculated from it.

To be consistent, also change X86_INTERNODE_CACHE_BYTES to
X86_INTERNODE_CACHE_SHIFT, and set it to 7 (128 bytes) for NUMA
to account for last level cache line size (which here matters
more than L1 cache line size).

Finally, make sure the default value for X86_L1_CACHE_SHIFT,
when X86_GENERIC is selected, is being seen before that for the
individual CPU model options (other than on x86-64, where
GENERIC_CPU is part of the choice construct, X86_GENERIC is a
separate option on ix86).
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Acked-by: NRavikiran Thirumalai <kiran@scalex86.org>
Acked-by: NNick Piggin <npiggin@suse.de>
LKML-Reference: <4AFD5710020000780001F8F0@vpn.id2.novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

A single 'movl' is shorter than the 'xorl'-'orl' pair.
No change in behaviour.
Signed-off-by: NAlexander Potashev <aspotashev@gmail.com>
LKML-Reference: <1256341043-4928-1-git-send-email-aspotashev@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This has the consequence of changing the section name use for head
code from ".text.head" to ".head.text".

Linus suggested that we merge the ".text.head" section with ".text"
(presumably while preserving the fact that the head code starts at 0).
When I tried this it caused the kernel to not boot.
Signed-off-by: NTim Abbott <tabbott@ksplice.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The absence of vmlinux.lds here keeps .vmlinux.lds.cmd from being
included, which in turn leads to it and all its dependents always
getting rebuilt independent of whether they are already up-to-date.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
LKML-Reference: <4A8D84670200007800010D31@vpn.id2.novell.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Enable gcov profiling of the entire kernel on x86_64. Required changes
include disabling profiling for:

* arch/kernel/acpi/realmode and arch/kernel/boot/compressed:
  not linked to main kernel
* arch/vdso, arch/kernel/vsyscall_64 and arch/kernel/hpet:
  profiling causes segfaults during boot (incompatible context)
Signed-off-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Li Wei <W.Li@Sun.COM>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

git status complains of untracked (generated) files in arch/x86/boot..

# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#       ../../arch/x86/boot/compressed/mkpiggy
#       ../../arch/x86/boot/compressed/piggy.S
#       ../../arch/x86/boot/compressed/vmlinux.lds
#       ../../arch/x86/boot/voffset.h
#       ../../arch/x86/boot/zoffset.h

..so adjust .gitignore files accordingly.
Signed-off-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

For relocatable 32bit kernels, boot/compressed/relocs.c processes
relocation entries in the kernel image and appends it to the kernel
image such that boot/compressed/head_32.S can relocate the kernel.
The kernel image is one statically linked object and only uses two
relocation types - R_386_PC32 and R_386_32, of the two only the latter
needs massaging during kernel relocation and thus handled by relocs.
R_386_PC32 is ignored and all other relocation types are considered
error.

When the target of a relocation resides in a discarded section,
binutils doesn't throw away the relocation record but nullifies it by
changing it to R_386_NONE, which unfortunately makes relocs fail.

The problem was triggered by yet out-of-tree x86 stack unwind patches
but given the binutils behavior, ignoring R_386_NONE is the right
thing to do.

The problem has been tracked down to binutils behavior by Jan Beulich.

[ Impact: fix build with certain binutils by ignoring R_386_NONE ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <4A1B8150.40702@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

arch/x86/boot/compressed/misc.c contains several sanity checks on the
output address.  Correct constraints that are no longer correct:

- the alignment test should be MIN_KERNEL_ALIGN on both 32 and 64
  bits.
- the 64 bit maximum address was set to 2^40, which was the limit of
  one specific x86-64 implementation.  Change the test to 2^46, the
  current Linux limit, and at least try to test the end rather than
  the beginning.
- for non-relocatable kernels, test against LOAD_PHYSICAL_ADDR on both
  32 and 64 bits.

[ Impact: fix potential boot failure due to invalid tests ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Make the kernel_alignment field adjustable; this allows us to set it
to a large value (intended to be 16 MB to avoid ZONE_DMA contention,
memory holes and other weirdness) while a smart bootloader can still
force a loading at a lesser alignment if absolutely necessary.

Also export pref_address (preferred loading address, corresponding to
the link-time address) and init_size, the total amount of linear
memory the kernel will require during initialization.

[ Impact: allows better kernel placement, gives bootloader more info ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Remove a couple of lines of dead code from
arch/x86/boot/compressed/head_*.S; all of these update registers that
are dead in the current code.

[ Impact: cleanup ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Use LOAD_PHYSICAL_ADDR instead of CONFIG_PHYSICAL_START in the 64-bit
decompression code, for equivalence with the 32-bit code.

[ Impact: cleanup, increases code similarity ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Determine the compressed code offset (from the kernel runtime address)
at compile time.  This allows some minor optimizations in
arch/x86/boot/compressed/head_*.S, but more importantly it makes this
value available to the build process, which will enable a future patch
to export the necessary linear memory footprint into the bzImage
header.

[ Impact: cleanup, future patch enabling ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

In the pre-decompression code, use the appropriate largest possible
rep movs and rep stos to move code and clear bss, respectively.  For
reverse copy, do note that the initial values are supposed to be the
address of the first (highest) copy datum, not one byte beyond the end
of the buffer.

rep strings are not necessarily the fastest way to perform these
operations on all current processors, but are likely to be in the
future, and perhaps more importantly, we want to encourage the
architecturally right thing to do here.

This also fixes a couple of trivial inefficiencies on 64 bits.

[ Impact: trivial performance enhancement, increase code similarity ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The 64-bit code already clears EFLAGS as soon as it has a stack.  This
seems like a reasonable precaution, so do it on 32 bits as well.

[ Impact: extra paranoia ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Set up the decompression stack as soon as we know where it needs to
go.  That way we have a full-service stack as soon as possible, rather
than relying on the BP_scratch field.

Note that the stack does need to be empty during bss zeroing (or
else the stack needs to be moved out of the bss segment, which is also
an option.)

[ Impact: cleanup, minor paranoia ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Both on 32 and 64 bits, we copy all the way up to the end of bss,
except that on 64 bits there is a hack to avoid copying on top of the
page tables.  There is no point in copying bss at all, especially
since we are just about to zero it all anyway.

To clean up and unify the handling, we now do:

  - copy from startup_32 to _bss.
  - zero from _bss to _ebss.
  - the _ebss symbol is aligned to an 8-byte boundary.
  - the page tables are moved to a separate section.

Use _bss as the copy endpoint since _edata may be misaligned.

[ Impact: cleanup, trivial performance improvement ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Clean up style issues in arch/x86/boot/compressed/head_64.S.  This
file had a lot fewer style issues than its 32-bit cousin, but the ones
it has are worth fixing, especially since it makes the two files more
similar.

[ Impact: cleanup, no object code change ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Reformat arch/x86/boot/compressed/head_32.S to be closer to currently
preferred kernel assembly style, that is:

- opcode and operand separated by tab
- operands separated by ", "
- C-style comments

This also makes it more similar to head_64.S.

[ Impact: cleanup, no object code change ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Use the BP_scratch symbol from asm-offsets.h instead of hard-coding
the location.

[ Impact: cleanup ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

When generating the compression suffix in
arch/x86/boot/compressed/Makefile, follow standard Kbuild
conventions, that is:

- Use a dash not underscore before y/m/n endings
- Use := whenever possible.
Requested-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Simplify the arch/x86/boot/compressed/Makefile, by using the new
capability of specifying multiple inputs to a compressor, and the
CONFIG_X86_NEED_RELOCS Kconfig symbol.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Acked-by: NSam Ravnborg <sam@ravnborg.org>

Aligning the .bss section makes it trivial to use large operation
sizes for moving the initialized sections and clearing the .bss.
The alignment chosen (L1 cache) is somewhat arbitrary, but should be
large enough to avoid all known performance traps and small enough to
not cause troubles.

[ Impact: trivial performance enhancement, future patch prep	]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Jesper reported that he saw following build issue:

 > ld:arch/x86/boot/compressed/vmlinux.lds:9: syntax error
 > make[2]: *** [arch/x86/boot/compressed/vmlinux] Error 1
 > make[1]: *** [arch/x86/boot/compressed/vmlinux] Error 2
 > make: *** [bzImage] Error 2

CPP defines the symbol "i386" to "1".
Undefine this to fix it.

[ Impact: build fix with certain tool chains ]
Reported-by: NJesper Dangaard Brouer <jdb@comx.dk>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.00.0904260958190.3101@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>